Liquid thermal conductivity prediction for alkanes, ketones and silanes

The values of thermal conductivity λ at different temperatures for organic and inorganic compounds in the liquid phase is required in the study of several processes, but experimental data are often not available with acceptable reliability or not available at all; since rigorous theoretical or semi-theoretical models of the liquid state are usually of poor practical use for engineering purposes (the errors can be very high and the mathematical difficulties generally lead to excessive simplifications) empirical or semi-empirical methods are used to estimate λ with reasonable accuracy. In this work a simple equation already proposed by the authors for the estimation of the liquid thermal conductivity of alcohols is generalized in order to allow the calculation of λ for the compounds belonging to the families of n-alkanes, ketones and silanes. The proposed equation requires for each compound the knowledge of the critical temperature Tc and the molecular weight M and contains three parameters: the ‘golden ratio’ Φ,, a factor h characteristic of the investigated organic family and an exponent a depending on the molecular structure. The families of n-alkanes, ketones and silanes were chosen to verify the general reliability of the method when used in large temperature ranges for very different organic families, above all the silanes (compounds containing silicon), whose liquid thermal conductivity is experimentally investigated in very few cases. The comparison between estimated and experimental λ values was developed taking into account the database due to ‘The DIPPR Information and Data Evaluation Manager’. The general equation appears to be successful: in the reduced temperature range 0.30–0.80, along or near the saturation line, the average absolute deviations between calculated and experimental thermal conductivity data are usually <4% and the maximum absolute ones usually <8%. A comparison is developed between the proposed equation and several correlations appeared in scientific and technical literature. The final goal to be reached is to cover by the proposed estimation method in general the different families of the organic compounds.